We are currently running varying degrees of tight oil at the majority or our refineries. At the refineries that are running a larger percentage of tight oil, the largest field impacts we have identified have been the shift to lighter products. At the same time, it insignificantly increased volume gains and significantly decreased slurry yield.

There are a lot of parts to this question, so I will respond to them independently. One of the catalyst design features that is important in any kind of feed, when you are going to get high iron and high calcium, is in the porosity. We talked a little before about how these contaminant metals tend to form these eutectics which can melt the surface of the catalyst and close off the pores.

The schematic on the slide shows the representation of the coke yield and the coke balance from the FCC. Of course, the total overall weight percent coke yield is set by heat balance, but the sources of the coke vary significantly from one feed to the next. Everyone talked thoroughly about how the coke precursors are just not there in these lighter feeds.

This answer will be very similar to what was already discussed about how to treat the resids. The example shown on the slide is a Maya blend, a typical tight oil, and then a tight oil with resid. Again, we are seeing significant reductions in sulfur and Conradson carbon metals and also a much higher hydrogen content.

I am going to take the question in a few parts. I will cover the reactor side first. In the reactor side, dipleg plugging will generally be due to coke formation that can be subdivided into two categories: the coke formation that occurs either internal to the cyclone or externally. On the gas outlet tube of the cyclone, you will see the stereotypical coke formation on the backside of the gas outlet tube, perhaps from incomplete feed vaporization.

In the history of our unit, there have been no outright failures of cyclones or cyclone supports, just partial failures. In our experience, the major cause of failure in cyclones and cyclone supports has been erosion leading to thinning, cracks, and breakages.

Proper design of cyclones and cyclone support systems will extend the life of cyclones with proper maintenance. But like the tires on your car, it will need to be replaced towards its end-of-life. Just like checking for remaining treads on your tire, one common way to check the remaining life of your cyclone is to measure and log the thickness of your cyclones for each turnaround from their first installations to last turnaround dates.

There are several KPIs that are tracked in the monitoring of FCC. Liquidy yields is one parameter that is monitored daily to detect any changes in equipment and catalyst performance.